<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <script>
    let a = 1;
    let b = 2;
    [a, b] = [b, a]

    console.log(a) // 2
    console.log(b) // 1

  </script>
</body>

</html>